1. Field of the Invention
The present invention relates generally to a radio frequency connector and, more specifically, to a non-contacting radio frequency connector that employs capacitive coupling.
2. Description of the Related Art
Traditionally, coaxial connectors and waveguide connectors have been used for connecting radio frequency circuits. Coaxial cables include an inner conductor and an outer conductor shield separated by a dielectric. Coaxial connectors usually have slip spring fingers for contacting the inner conductor of a coaxial cable. After a period of time and repeated connections, the slip spring fingers and the inner conductors corrode and platings thereon wear off. Also, after repeated connections, the inner conductor tends to bend out of contact with the slip spring fingers. Each of these effects can result in a non-connection, a high voltage standing-wave ratio (VSWR), and arcing.
Waveguide connectors usually bolt together at their flanges, and generally require an inside width of at least .lambda./2 in order to transmit a signal (where .lambda. is the wavelength of the signal to be transmitted). Also, a waveguide connector requires a balun, i.e., a network for the transition from an unbalanced transmission line to a balanced transmission line, having a transition length of .lambda./4. Consequently, a waveguide connector is relatively large. Though a waveguide connector can be made smaller with dielectric loading, dielectric loading results in increased insertion loss.
Connection to a microstrip lead of a radio frequency microstrip circuit, e.g., a transmitter/receiver module, may be made by transition to a stripline, a coaxial connector or a microstrip wire bonded to another microstrip radio frequency circuit. Connection to a stripline lead of such a radio frequency microstrip circuit may be made by press mating with another stripline. Each of these connections is bulky and inherently involves contact complexity. Also, each of these connections, except for the coaxial connector, requires connection in a plane parallel to the plane of the substrate of the radio frequency microstrip circuit. Only the coaxial connector permits connection at any angle with respect to the plane of the substrate of the radio frequency microstrip circuit. However, coaxial connectors are bulky and their performance deteriorates over time and after repeated connections.
Consequently, there is a need for a radio frequency connector that may be made small without increasing insertion loss; that is not subject to an increased VSWR, arcing and non-connection over time and after repeated connections; and that permits connection at any angle relative to an input or output lead.